Y pipe doesn't fit...

[nola mike]

Still waiting to get to the easy part of this swap...

Went to bolt on the y pipe today, and found that only 3 of the 4 bolt holes lined up. The upper left holes don't align. I thought I remembered seeing a 3 v 4 bolt design either in a manual or parts diagram, but don't see it now. The donor y pipe is from an 89, and the transom plate is 86. The donor is a 4.3, the recipient is a 3.7. the donor transom assembly is unavailable for comparison until next week. It doesn't appear that the transom plates are different between engines, so what gives? I found a few threads by Fishermark , including this one: https://forums.iboats.com/forum/engi...cruiser-y-pipe

At this point, if I want to boat I need to give it a shot and see if it leaks, but would like to know what's correct.

 

[Fishermark]

Hi Mike - I just saw this post. I never had any issues with the three bolts - it worked fine for years with no leakage.

 

[Bondo]

Ayuh,...... As long as the rubber gasket is supported all round, 3 bolts will work as good as the 4 bolts,....

 

[nola mike]

Interesting. We'll see. I looked at a couple of gimbal housings that I have, and there are indeed at least 2 styles. There is only 1 part number listed for the a1g1, so wondering if the old ones were superceded by the 5 bolt style?